2-Hydroxyisobutyric acid → HCID 89668696, compound

Participants

Reaction Conditions

Reaction Steps

Oxalyl chloride (1.17 mL, 13.3 mmol) was added dropwise to a solution of (S)-1-(((9H-fluoren-9-yl)methoxy)carbonyl)pyrrolidine-2-carboxylic acid (Fmoc-Pro-OH) (3.00 g, 8.89 mmol) and N,N-dimethylformamide (34 μL, 0.445 mmol) in methylene chloride (36 mL) with stirring at 0° C. under a nitrogen atmosphere, and the reaction mixture was then stirred at room temperature for 1 hour. The reaction solution was concentrated under reduced pressure, the resulting residue was mixed with methylene chloride (36 mL), N-ethyldiisopropylamine (DIPEA) (4.66 mL, 26.7 mmol) and 2-hydroxy-2-methylpropanoic acid (2.78 g, 26.7 mmol) at 0° C., and the reaction mixture was stirred at room temperature for 2 hours. The reaction solution was washed with 1 N hydrochloric acid twice and a saturated aqueous sodium chloride solution twice, dried over sodium sulfate and then concentrated under reduced pressure. The resulting residue was purified by reverse-phase silica gel column chromatography (0.1% aqueous formic acid solution/0.1% formic acid-acetonitrile solution) to afford (S)-2-((1-(((9H-fluoren-9-yl)methoxy)carbonyl)pyrrolidine-2-carbonyl)oxy)-2-methylpropanoic acid (Fmoc-Pro-HOGly(Me)2-OH) (Compound SP636) (3.70 g, 8.74 mmol, 98%).

Provenance & Evidence